Vertical axis wind or water turbine shield shape.

摘要

A wind or water turbine comprises a rotor having a rotational axis and blades 104 spaced from and parallel to the axis defining a cylindrical space within the rotor through which flow W passes. A returning blade flow shield V3 is defined by a radially inward surface following the rotor circumference and a radially outward surface which comprises a first portion meeting the inward surface. The first portion extends in a first direction n at an angle of at least 0 and up to 90 degrees relative to the rotor radial direction r1 in the rotor contra-rotational direction. The outward surface also comprises a second portion which meets the first portion and which extends in a second direction p that makes an angle of more than 180 degrees in the contrarotational direction relative to the first direction n The directions may be curved surface tangents Improves power output and efficiency.